Tape Cartridge Provided With A Display Portion

Abstract

A tape cartridge containing therein a printing tape for use with a compact electronic computer. The tape may readily be set with respect to the computer body, and printing may be effected on the tape at an exposed portion of the cartridge by the printing device of the computer and information so printed on the tape may be viewed through a viewing window provided in the computer as the tape moves through a viewing section formed in the cartridge. The lock means is provided in the cartridge for cooperating with retaining rollers in the computer to positively and removably fix the cartridge when inserted in the computer body, a resilient member being provided in the cartridge for accomplishing smooth movement of the printing tape.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a tape cartridge for use with an electronic computer, and more particularly to a tape cartridge removably inserted in an electronic computer and containing therein a tape on which digits and results of operations are printed in accordance with signals from the computer so that such information may be displayed through a display section while the tape is moved.

2. Description of the Prior Art

In compact electronic computers such as desk-set computers, digits entered and results of operations have usually been displayed by a system using a row of numerical display tubes disposed in a portion of the computer body and selectively turned on in accordance with the digits entered or the results of operations effected, but such a display system has not been useful to keep the displayed records for future use.

To overcome such a disadvantage, it has been proposed to provide a computer body with a mechanism for holding a roll of paper, a mechanism for feeding the paper, and a printing mechanism for printing digits and symbols on the paper fed by the paper feeding mechanism so that those digits and symbols printed on the paper may be read. The described system using such paper for printing the output of a computer has become widely used because of its advantage that the paper carrying printed information thereon can be directly used as means for checking or storing the results of the calculations effected, but it has required much time for setting the printing paper to the computer body and often involved certain dangers. More particularly, a roll of paper to be printed must be fixed in a predetermined position with its leading edge nipped between feed rollers, and if the printing system in use is of an electric discharge type, means such as a discharge circuit supplied with a high voltage which might be dangerous to the human body is provided adjacent to the feed path of the paper. The term "printing" used herein includes not only the ordinary type of printing whereby characters are imprinted under pressure on paper but also other types of printing such as the discharge printing which uses a discharge stylus adapted to scan discharge destroying paper for selective discharge to thereby represent any desired pattern on the paper or the thermal printing which uses heating elements selectively driven to print any desired pattern.

The above-noted disadvantages peculiar to the prior art may be overcome by a tape cartridge provided according to the present invention.

SUMMARY OF THE INVENTION

It is an object of the present invention to accommodate a tape of printing paper within a cartridge and readily enable such paper to be set with respect to a computer body.

It is another object of the present invention to provide printing means and reading means in the path of said printing paper moving in the cartridge to thereby enable information printed on the paper to be read from outside the cartridge.

It is still another object of the present invention to provide a cartridge in which the paper tape may be inclined as it moves through the reading means, thereby enabling the information on the tape to be readily read.

It is yet another object of the present invention to provide lock means in the cartridge for correctly and removably fixing the cartridge to a computer body.

It is still another object of the present invention to provide retaining means in a computer body for cooperating with said lock means to effectively fix the cartridge to the computer body.

It is still another object of the present invention to provide a cartridge having a resilient member for accomplishing smooth movement of the tape.

These and other objects and advantages of the present invention will become fully apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a compact electronic computer and a tape cartridge containing therein a printing tape to be set to the computer.

FIG. 2 is a perspective view of the tape cartridge for illustrating the interior thereof in greater detail.

FIG. 3 is an exploded perspective view of the cartridge shown in FIG. 2.

FIGS. 4(a) to 4(d) illustrate an angle changing member used for inclining the tape.

FIG. 5 is a perspective view showing the bottom of the cartridge.

FIG. 6 is a fragmentary perspective view of the computer for illustrating retaining means provided in the computer body for retaining the cartridge thereto.

FIG. 7 is a bottom plan view of the computer body for further illustrating lock means provided therein for cooperating with the retaining means of FIG. 6 to fix the cartridge to the computer.

FIGS. 8(a) and 8(b) illustrate the manner in which the cartridge is retained by cooperation between the retaining means of FIG. 6 and the lock means of FIG. 7.

FIG. 9 is a perspective view of the tape driving system.

FIG. 10 is an exploded perspective view for illustrating the plunger portion of the driving system.

FIG. 11 is a side view of the driving system.

FIG. 12 is a vertical sectional view of the driving sytem of FIG. 11.

FIG. 13 is a vertical sectional view of the tape feed mechanism.

FIGS. 14(a) and 14(b) are cross sectional views of the tape driving roller taken along section line 14--14 of FIG. 13.

FIG. 15 is a cross-sectional view taken along section line 15--15 of FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is shown a computer body generally designated by 11 and a tape cartridge generally designated by 12 which is to be inserted into the computer body 11. The computer body 11 accommodates therein various circuits (not shown) such as digit entering circuit, operating circuit, display circuit, etc. and can perform as an independent computer. In the forward upper surface of the computer body 11 there are provided digit entering keys 13 for entering digital data and function keys 14 for effecting various calculations on such digital data. The tape cartridge 12 contains therein a roll 25 (FIG. 2) of narrow tape strip 17 wound in the form of a coil and rotatably held so as to be freely unwound. The cartridge 12 has a recess 15 and a viewing section 16 both formed in the front end thereof so that tape 17 unwound from said roll 25 may be imprinted with characters at the front recess 15 by a thermal head or printing means 42 (FIG. 6) provided in a portion of the computer body 11 corresponding to the recess 15 as will be described later, and then guided through the viewing section 16 which is generally sloped, preferably at 45.degree., to enable the information printed on the moving tape to be readily read from outside the cartridge 12. A viewing window 18 is provided in a portion of the computer body 11 corresponding to the viewing section 16 of the tape cartridge 12 so that when the cartridge 12 is inserted into the computer body 11 the digital information on the tape 17 moving through the viewing section 16 may be viewed from outside the computer body 11. The viewing window 18 of the computer body 11 is also sloped complementarily to the viewing section 16 of the cartridge 12 so as to facilitate the read out of the printed information on the tape 17.

It will thus be seen that the above-described computer is not of the type which has a fixed display means but of the type in which a tape 17 imprinted with information is moved in the cartridge 12 so that information on the tape may be read as it runs along its path of movement and thus preservation of such tape 17 provides preservation of the results of calculations effected by the computer. Moreover, the tape setting may be accomplished simply by inserting the cartridge 12 into the computer body 11.

FIGS. 2 and 3 illustrate the tape cartridge 12 in greater detail. As shown, the tape cartridge 12 comprises a bottom member 19 and a top cover 20 both formed of a material such as plastic or the like. The bottom member 19 includes a bottom plate 21 and three side plates 22, 23 and 24. Substantially in the center of the bottom plate 21 there is formed a core 26 for rotatably holding thereon a tape roll 25 from which the tape 17 may be freely supplied. A resilient member 27 to be described may be fixedly held in the bottom member 19 by holder members 28 and 29 formed therein, and a keep member 30 also to be described may be held in the bottom member 19 by holder members 31 and 32 formed therein.

The resilient member 27 generally takes a U-shaped configuration, and one end thereof forms a U-shaped portion 33 for bearing against the tape 17, while the other end carries a rotatable roller 34 to provide a tape feeder portion cooperable with a drive roller 49 (FIG. 6) to be described.

The tape cartridge 12 is such that when the printing tape 17 is driven to effect printing or display of prints by the drive roller 49 in the direction as indicated by an arrow C in FIG. 2, the tape 17 is taut and the shock absorbing portion 27' of the resilient member 27 flexes inwardly toward the tape roll 25. In other words, since the inertia of the tape roll 25 due to its mass is great as compared with the drive of the tape 17, the tape roll 25 itself is not substantially rotated and the drive of the tape 17 is absorbed by the shock absorbing portion 27'. Subsequently, the tape 17 roll 25 is rotated by the return force of the flexed shock absorbing portion 27' as it returns to its normal position so as to provide a sufficient slack of the tape 17 for a next printing process. Thereafter, the tape 17 is again subjected to a drive and moved to allow a printing and display of the print to take place, thus gradually increasing its tension to thereby flex the shock absorbing portion 27' again. When the drive to the tape 17 is stopped, the flexed shock absorbing portion 27' again returns to its normal position to allow the rotation of the tape roll 25. By repeating the described operation, smooth and intermittent tape feed may be accomplished at high speeds.

The keep member 30 has a pad 35 of felt or like material attached to one end thereof which is mounted adjacent the printing device 42 (FIG. 6) provided in the computer body 11, and this keep member 30 is provided so that the heat retaining characteristic of the felt pad 35 thereof may help to retain heat in the heatsensitive tape 17 at a portion thereof to be printed prior to the printing process, thereby increasing the print sensitivity or responsiveness of the tape 17 so as to ensure printing is effected on the tape 17 as well as to ensure the movement of the tape 17 through the viewing section 16. The felt pad 35 of such heat retaining characteristic is also useful to greatly increase the service life or durability of the thermal printing head 42, FIG. 6.

The top cover 20 includes a top plate 36, a transparent front end plate 37 forming the viewing section 16, and an angle changing member 38 depending from the top plate 36, the front end plate 37 and angle changing member 38 being both inclined substantially at 45.degree. with respect to the bottom plate 21. Between the front end plate 37 and the angle changing member 38 there is formed a cut-away 39.

Numeral 40 designates a low friction sheet formed of Teflon (trade name) to be interposed between the tape roll 25 and the bottom plate 21 so as to facilitate the rotation of the tape roll 25. Numeral 41 designates a conically shaped angle changing member depending from the top plate 36 for changing the angle at which the tape 17 moves.

To assemble the parts of FIG. 3 into the complete tape cartridge 12 as shown in FIG. 2, the low friction sheet 40 is first inserted over the core 26 in the bottom plate 21, and then the tape roll 25 is inserted similarly in superposed relationship on the sheet 40. The resilient member 27 is fixed to the holder members 28 and 29, while the keep member 30 is fixed to the holder members 31 and 32 at an angle approximately equal to that of the front end plate 37. Thereafter, the top cover 20 is fixed to the bottom member 19 with the pad 35 of the keep member 30 positioned in the cut-away 39 formed in the upper cover 20. There is thus provided a tape cartridge assembly 12.

In such a tape cartridge 12, the tape 17 unwound from the tape roll 25 has its direction of movement changed by the U-shaped portion 33 of the resilient member 27 so as to be guided along the member 27 and then led out of the cartridge 12 between the side wall 24 and the angle changing member 38 to change its direction of movement so as to pass through the cartridge 12 between the keep member 30 and the front end plate 37. Thus, the tape 17 moves between the keep member 30 and the front end plate while keeping an angle of about 45.degree. with respect to the bottom plate 21. In other words, the tape 17 has its printing surface somewhat inclined upwardly as it passes through the viewing section 16. Such inclined position of the printing surface in the viewing section 16 is greatly useful to facilitate the read out of the printed information on the tape 17.

As noted above, the resilient member 27 bears against the tape 17 as the latter is unwound from the supply roll 25, and therefore, when the tape 17 is intermittently driven to move, a tension sharply developing in such driven tape 17 will be absorbed by the resilient member 27, which will thus flex inwardly to prevent any excessive force from being imparted to the tape 17 and enable very smooth feed of the tape 17.

FIGS. 4(a) - 4(d) further illustrate the angle at which the tape 17 is moved in the described manner. FIGS. 4(a) and 4(b) are front and right side views, respectively, of the angle changing member 38. If the angle changing member 38 forms an angle of approximately 45.degree., for example, with respect to the bottom plate 21 as shown in FIG. 4(b), one side edge 38' of the member 38 will also have an angle of approximately 45.degree. as shown in FIG. 4(a). Thus, the angle changing member 38 serves to smoothly change the direction of movement of the tape 17 and thereby eliminate any danger of severing the tape 17 which would otherwise result from an excessive force imparted to the tape 17 when it is suddenly turned to the direction along the front end plate 37 after travelling along the resilient member 27 while keeping its upright position with respect to the bottom plate 21. FIGS. 4(c) and 4(d) are front and left side views, respectively, of the conically shaped angle changing member 41 disposed at a terminus in the path of the tape 17 for recovering the upright position of the tape 17 after it has travelled along the front end plate 37 while keeping the angle of 45.degree. with respect to the bottom plate 21.

As described just above, the angle of the tape 17 with respect to the bottom plate 21 is provided by the angle changing member 38 before the tape reaches the front end plate 37, then the tape 17 passes through the cut-away 39 to reach the front end plate 37. In the cut-away 39 there is positioned the pad 35 of the keep member 30 as described previously, so that when the cartridge 12 is inserted into the computer body 11 the tape 17 moves between the pad 35 and a thermal head 42 comprising a column of four selectively movable dots and a row of five selectively movable dots. While so moving, the tape 17 is urged into contact with the thermal head 42 by a suitable pressure so that printing may be effected always under good conditions, and the information thus printed on the tape 17 may be viewed from outside the cartridge 12 through the transparent front end plate 37.

As shown in FIG. 5, the underside of the cartridge 12 is substantially flat and has a lozenge-shaped projection or retaining member 43 formed in the forward center thereof. The retaining member 43 serves to force the tape cartridge 12 toward the thermal head 42 with a predetermined pressure once the cartridge 12 has been inserted into the computer body 11. This is accomplished with the aid of a pair of rotatable rollers 44 and 45 urged toward each other as shown in FIG. 6. For this purpose, the computer body 11 is formed with a channel 46 along which the projected retaining member 43 slides when the tape cartridge 12 is received into the computer body 11, and further formed with stoppers 47 and 48 for positioning the inserted cartridge 12 in place. As shown, the computer body 11 is provided with a tape driving roller 49 adapted to nip and drive the tape 17 between itself and the roller 34 at one end of the resilient member 27 disposed within the tape cartridge 12.

FIG. 7 shows a driving mechanism for the pair of rollers 44 and 45. Two arms 50 and 51 are pivotally mounted at one end on shafts 52 and 53 and provided with retainer means 54 and 55, which are biased toward each other by a spring 56. Secured to the other ends of the respective arms 50 and 51 are shafts 57 and 58, on which the rollers 44 and 45 are rotatably mounted in an opening 58'. Since the rollers 44 and 45 are normally biased toward each other by the spring 56, once the tape cartridge 12 is inserted into the computer body 11, the lozenge-shaped retaining member 43 is snapped between the rollers 44 and 45 to further push aside these two rollers 44, 45 against their closing forces as shown in FIG. 8(a) until the apexes 59 and 60 of the lozenge-shaped retaining member 43 pass the rollers 44 and 45 to come to a position as shown in FIG. 8(b), whereupon the rollers 44 and 45 are caused to come toward each other by the spring 56. Thus, the retaining member 43 and accordingly the tape cartridge 12 is subjected to a force directed as indicated by the solid-line arrow D. When assuming the position as shown in FIG. 8(b), the tape cartridge 12 is restrained by the stoppers 47 and 48 and thus retained in a position where it is constantly urged toward the thermal head 42 or in the direction as indicated by the dotted-line arrow E.

The removal of the tape cartridge 12 from the computer body 11 may be accomplished by pulling back the cartridge 12 so as to displace the retaining member 43 in the direction opposite to that indicated by the dotted-line arrow E, FIG. 8(b) until it forcibly opens the rollers 44 and 45 to pass therebetween and disengage therefrom.

In the illustrated example, the retaining member 43 is shown as a lozenge shape, whereas this is not the only possible shape but the retaining member 43 may take any other suitable shape such as ellipse which converges in two directions so as to allow the insertion and removal of the cartridge 12 by cooperation with the rollers 44 and 45 in the described manner.

As noted above, the cartridge 12, once inserted in the computer body 11, may always be urged toward the thermal head 42 with a predetermined force by the retaining rollers 44, 45 provided in the computer body 11, so that the tape 17 supplied from within the the cartridge 12 may be nipped between the roller 34 and the driving roller 49 and intermittently fed by intermittently driving the roller 49.

Referring to FIGS. 9 to 15, the system for intermittently feeding the tape 17 is shown in greater detail. In front of a plunger case 61 there is a rack 62 formed at the forward end portion of a plunger actuator 63. An arm 64 for holding the rack 62 is secured to a base plate 65. A gear 66 meshing with the rack 62 is mounted on a main drive shaft 67 for rotation therewith. A return spring 68 is provided to normally bias the main drive shaft 67 for clockwise rotation. An auxiliary drive shaft 69 is loosely fitted on the main drive shaft 67 in a manner to be described, and it has a one-way rotating mechanism mounted on its inner side wall. A driving roller 49 of rubber which has already been described is mounted around the auxiliary drive shaft 69, and a resilient disc 70 is secured to the main drive shaft 67, the disc 70 having spring arms 71 and 72 for resiliently pressing followers 81 and 82 (FIGS. 14a and 14b) which will be described later. A unit fixing plate 73 formed of a resilient material is secured to the top of the plunger case 61 and has fixed mounting arms 74, 75 and 76 of a U-shaped cross-section and capable of absorbing any shock imparted thereto by the reciprocation of the plunger actuator 63. The base plate 65 is secured to the plunger case 61 to receive actuator 63 and carry the driving roller 49, thereby forming a part of the tape driving system. A shock absorbing member 77 formed of rubber or like material is fitted to the base of the rack 62 extending from the plunger actuator 63, so as to absorb the shock imparted by the actuator 63 when it is returned by the force of the spring 68 and strikes the holding arm 64.

As shown in FIG. 14(a), a cam 78 is formed below the resilient disc 70 and at the upper end of the main drive shaft 67. The cam 78 is formed with cam portions 79 and 80 for receiving therein cylindrical followers 81 and 82 respectively. The spring arms 71 and 72 formed in the resilient disc 70 bear against the cylindrical surfaces of the respective followers 81 and 82 to bias these followers 81, 82 toward the inner side wall 83 of the auxiliary drive shaft 69. Thus, when the main drive shaft 67 is rotated in the direction indicated by arrow A to drive the cam 78 to rotate in the same direction, the followers 81 and 82 will be trapped in the wedge-shaped spaces defined between the cam portions 79, 80 and the inner wall 83 of the auxiliary drive shaft 69 to rotate this shaft 69 also in the direction of the arrow A. If the main drive shaft 67 is rotated in the direction opposite to that indicated by the arrow A, the cam 78 will also be rotated in such opposite direction to cause the spring arms 71 and 72 to follow the rotation of the cam 78, whereby the spring arms 71 and 72 will force the followers 81 and 82 to follow only the cam 78 along the cam portions 79 and 80, thus releasing the operative engagement between the main and auxiliary drive shafts 67 and 69 (See FIG. 14(b). The auxiliary drive shaft 69 is further formed with an intermediate wall surface 83, beneath which is disposed a cam 86 loosely fitted concentrically with the main drive shaft 67 and fixed to the base plate 65 by means of screws 84 and 85.

The cam 86 has two symmetrical cam portions 87 and 88 similarly to the cam 78, and cylindrical followers 89 and 90 are received in these cam portions 87 and 88 respectively. When the cam 86 is fixed to the base plate 65, a resilient pressure plate 91 (FIG. 13) similar in shape to the resilient disc 70 is fixed integrally to the fixed base of the cam 86 and the followers 89 and 90 are resiliently pressed by spring aims 92 and 93 in the same way as the followers 81 and 82, as shown in FIG. 15. Therefore, when the cam 78 on the main drive shaft 67 is rotated in the direction of arrow A, the auxiliary drive shaft 69 will also be rotated in the same direction so that the followers 89 and 90 in the cam 86 secured to the underside of the cam 78 are rotated within the inner wall of the auxiliary drive shaft 69 and forced out of the wedge-shaped spaces defined by the inner wall of the auxiliary drive shaft 69 and the cam portions 87, 88 of the cam 86 so as to bear against the spring arms 92 and 93. In this way, the rotation of the main drive shaft 67 in the direction of arrow A may be transmitted to the auxiliary drive shaft 69.

When the main drive shaft 67 is rotated in the direction or arrow B opposite to the direction of arrow A, the auxiliary drive shaft 69 is prevented from following the rotation of the cam 78 because the followers 89 and 90 therebelow are then trapped in the wedge-shaped spaces defined by the cam portion 87 and 88 of the cam 86 and the inner wall of the auxiliary drive shaft 69, which is thus immovably fixed to the cam 86 by the followers 89 and 90. On the other hand, the cam 78 and accordingly the main drive shaft 67 may be rotated while the spring arms 71 and 72 thereof are pressing the followers 81 and 82.

It will thus be appreciated that the different pairs of followers 81, 82 and 89, 90 resiliently pressed in the same direction allow the auxiliary drive shaft 69 to rotate only in the direction of arrow A in response to the reciprocal rotation of the main drive shaft 67, but the rotation of the auxiliary drive shaft 69 in the direction of arrow B opposite to the direction of arrow A is prevented due to the followers 89, 90 trapped in the wedge-shaped spaces.

In using the above-described cartridge 12 with the computer body 11, the tape 17 is initially drawn to the exposed roller 34 arms then the cartridge 12 is inserted into the cartridge receiving portion in the computer body 11, whereby the retaining member 43 at the bottom of the cartridge 12 is nipped between the pair of rollers 44, 45 and forced toward the printing head 42 (FIG. 6) at a predetermined pressure until the tape portion exposed at the cut-away 39 is brought into intimate contact with the printing head 42 while the leading edge of the tape 17 is nipped between the roller 34 and the driving roller 49.

If an operator closes a conventional power switch (not shown) and depresses desired digit entering keys 13 and function keys 14 to effect an operation, the entered digits and the result of the operation will be applied one by one to the printing head 42 through a conventional operating circuit (not shown).

In response thereto, an operating current flows into the plunger in the tape driving system so that the actuator 63 is attracted against the force of the spring 68 in the direction as indicated by arrow P in FIG. 12. As a result, the gear 66 is rotated counter-clockwise to cause the main drive shaft 67 to rotate in the direction of arrow A. As described above, such rotation of the main drive shaft 67 in the direction of arrow A causes the auxiliary drive shaft 69 to be rotated in the same direction due to the followers 81 and 82 being then trapped in the wedge-shaped spaces defined by the cam 78 and the inner wall of the auxiliary drive shaft 69, so that the printing tape 17 in the cartridge 12 is driven to move only a distance corresponding to one impressed character. Subsequently, when a printing current flows into the thermal head 42, the plunger operating current is cut off to allow the actuator 63 to be returned in the direction opposite to the direction of arrow P by the return spring 68 wound around the main drive shaft 67. The actuator 63 strikes the end of the rack holding arm 64, but the shock arising therefrom is absorbed by the shock absorber 77 fitted to the actuator 63 and the resilient U-shaped arms 74-76.

For the return movement of the actuator 63 or the reverse rotation of the main drive shaft 67 in the direction opposite to the direction of arrow A, the auxiliary drive shaft 69 is prevented from rotating by the cooperation between the cam 86 and associated followers 89, 90, resulting in idle rotation of the main drive shaft 67 and no movement of the tape 17.

In this way, the tape driving system drives to move the tape 17 a distance corresponding to one impressed character each time printing is effected by the printing head 42.

Thus, the data printed successively on the tape 17 are moved to reach the viewing section 16 of the cartridge 12 so that the information representing the entered digits and the results of the effected calculations can be read through the viewing window 18 provided in the computer body 11.

Claims

We claim:

1. A tape cartridge comprising:

a printing tape wound in a roll for unwinding in succession;

a case for housing said printing tape therein;

holding means in said case for holding said roll of printing tape;

a tape advancing path in said case for advancing said printing tape unwound from said roll within said case;

a printing section in said case in said tape advancing path to effect printing on said printing tape sequentially in the lengthwise direction of said printing tape in accordance with the advancement of said printing tape by an externally provided printing device;

a visual observing section in a portion of said case downstream of said printing section with respect to the advancing direction of said printing tape in the tape advancing path for observing a plurality of prints on said printing tape printed at said printing section at a time in accordance with the advancement of said printing tape; and

a tape discharging portion at the end of said tape advancing path for discharging the printing tape passing through said visual observing section out of said case.

2. A tape cartridge according to claim 1, wherein said printing section comprises a cut-away portion provided in said case.

3. A tape cartridge according to claim 1, wherein said tape cartridge further comprises means for changing the angle of advancement of said printing tape with the aid of a tape angle changing member provided in a portion of the path of said printing tape upstream of said visual observing section, thereby inclining said printing tape as said printing tape advances through said visual observing section.

4. A tape cartridge according to claim 3, wherein said visual observing section of said tape cartridge is provided with an inclination approximately in parallel with the inclination of said printing tape corresponding to said tape angle changing member.

5. A tape cartridge according to claim 1, wherein said tape cartridge comprises a projection having two side edge portions disposed on the outer surface of said case, and wherein one of said side edge portions converges in one direction and the other side edge portion converges in the direction opposite to said one direction.

6. A tape cartridge according to claim 1, wherein said tape cartridge comprises a resilient member disposed along at least a portion of the tape advancing path of said printing tape from said roll, said resilient member having at least one end for resiliently bearing against said printing tape to absorb a tension in said printing tape.

7. A tape cartridge according to claim 6, wherein said resilient member has another end positioned in the vicinity of said printing tape passing through said visual observing section and has a roller at said another end.

8. A tape cartridge according to claim 6, wherein said one end of said resilient member resiliently bearing against said printing tape is formed into an arcuate shape.

9. A tape cartridge according to claim 6, wherein said tape cartridge further comprises at least two holding members formed in a position of said case for holding said resilient member.

10. A tape cartridge according to claim 2, wherein said printing section includes pressing means for continuously pressing said printing tape from inside said case toward the outside of said case.

11. A tape cartridge according to claim 3, wherein said tape cartridge further comprises a second tape angle changing member provided between said visual observing section and said tape discharging portion.

12. A tape cartridge according to claim 11, wherein said second tape angle changing member includes means for restoring the changed tape running angle substantially to the original angle.

13. A tape cartridge according to claim 11, wherein said tape cartridge further comprises a nip means for nipping the tape discharged with a roller mounted exteriorly of said tape cartridge at said tape discharging portion.